The United States of America As Represented by the Secretary of

Government of the United States of America, As Represented by the Secretary of Commerce

Robert E Lowry

Francis W Wang

Charles L Thomas

Anthony J Bur

King-Fu Lin

Steven C Roth

The change in the peak fluorescence wavelength of a small amount of a fluorescent compound, i.e., a fluorophore, which has been dissolved in a polymerizing material or a thermoplastic polymer is used to determine the extent of cure or solidification, respectively. The measured wavelength-shift can either be compared with a previously determined correlation to obtain an absolute value for the extent of cure, or can be utilized to compare or maintain an acceptable extent of cure throughout a manufacturing or a clinical process. Similarly, in the processing of a thermoplastic polymer by injection molding, the measured wavelength shift can either be compared with a previously determined correlation to obtain an absolute value for the temperature of the polymer, or can be utilized to adjust the injection molding cycle so that the mold is opened at the optimum times. The fluorophores used in the method are preferably selected from a class of fluorophores comprising alpha, omega substituted linear alkenes having an electron accepting group attached at the alpha position and an electron donating group attached at the omega position.

Non-destructive method for determining the extent of cure of a

A method of measuring fluid properties of a polymer melt, undergoing shear and/or extensional flow which utilizes fluorescent anisotropy. The method utilizes a polymeric chromophore which includes a bifunctional anthracene that is covalently bonded to polybutadiene. The invention also involves an optical probe which is designed to be inserted into existing temperature and/or pressure probe ports in processing equipment. The probe includes a rotatable polarizer and emission collection fibers.

Optical sensor for the measurement of molecular orientation and

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Falls Church, VA, United States of America

Robert E Lowry